Here is my start on the wiring. I will readily admit to being a novice, tilting more to the mechanical side than the electrical. You know, if you cant fix it with a bigger hammer...you've got an electrical problem.

I have posilocks on the way to help with the interconnects, but will really need some help understanding the "from" stock wiring and "to" where on the amp. Based on Robert's earlier comments, I assume I'm tapping two inputs going into the factory amp and connecting those to the RCA jacks. I further assume there is also a trigger wire for the "turn on" lug on the Arc amp. I have the FSM and will start trying to identify the appropriate wires this weekend.